Please help explain the numbers I am seeing...

[jtech1]

I was away for the last two weeks. I took everyone's advice on here and left the pool partially covered with solar cover (75%), left SWG running at slightly more than normal % (not under IntelliChem control) and used IntelliChem to just monitor pH. I came back and the pool is clear. I measured levels with my test kit and pH agreed with IntelliChem at 7.7 (steadily went up from 7.4 to 7.7 over the two weeks based on history graph), so I added enough acid to get it to 7.5, and FC was at 8.0 (slightly high, but I expected that since I was running SWG higher % than normal) and TC was 8.5. All seemed good! I removed the cover and started the robot pool cleaner. This morning when I check the levels, IntelliChem was reporting 8.0 pH, and my test kit confirmed it. Also, the FC dropped to 6.0 and CC shot up to where I stopped adding drops and it was still pink.

If this were an ammonia issue, why did it not show on my first tests? Here are my other levels:

CYA=55
CH=300
TA=80
Salt=3400

I'd appreciate any advice on what might be causing this? Do I shock and add more acid, or are these numbers being skewed by something else?

 

[Bama Rambler]

Did you test the CYA again? Just to make sure it didn't get converted.

It could just be a test anomaly.

I'd test everything again with a fresh sample.

 

[jtech1]

I had checked CYA and it was still at 50. But I reran the FC test right now and now it reads the same as yesterday. I think I may have messed up the errant test... I recall that I had the 10ml sample in the stirrer and added two drop first, then realized I had not put the powerd in, so I added the powder, then the rest of the drops to go clear. I just assumed that once mixed, the order of addition was not important... may be I was wrong?

So, it looks like FC/TC is fine... I'll check a little later also to confirm. But does it make sense that the pH would jump 0.3 after removing the cover? May be water on top of the cover mixing in when removed? Debris on the cover getting in the pool?

 

[Bama Rambler]

The pH thing could have been a mixing thing. The pool water may have had a higher pH near the surface or on the cover and when you removed and started everything it mixed well and caused a higher reading.

 

[jtech1]

May be... but I had the main drain and skimmers pulling for the filter pump, and IntelliChem matched the 7.7 that the test kit showed.. IC jumped to 8.0 after the cover was off also. I did have a lot of those caterpillar like tree droppings on the cover... I wonder if they raise the pH of the water enough that dumping that water back into the pool cause that much of a pH difference.